With the rapid development of the communication industry, a future network presents higher technical challenges to the communication technology, and resource conservation and efficiency enhancement become subjects of future network development. Green communication emerges on this back ground. The conventional wireless network has disadvantages such as high channel fading, high system power consumption, and poor received signal quality, due to limitations of the external environment where the wireless network locates and hardware conditions of its own devices. However, in a collaborative communication technology, a wireless terminal can be fully utilized to establish multiple communication links between the transmission end and the reception end, and fading in wireless channels can be overcome using space diversity in the conventional multi-antenna technology, thereby improving the performance and robustness of the wireless network system. In the collaborative communication, how to perform relay selection and power allocation is an important factor that affects the performance of the system.
With the collaborative communication technology, power consumptions and energy consumptions of the network system can be effectively reduced without affecting the quality of services provided to the users, thus the network energy utilization efficiency can be enhanced. Further, cellular spectrum reuse can be enhanced by using the D2D technology, improving spectrum efficiency, and increasing a network system capacity.